A radar system includes an antenna array including a plurality of antenna elements; and a transmitter portion coupled to the antenna array, the transmitter portion being configured to sequentially transmit a first transmit beam and a second transmit beam from a single pulse, the first transmit beam and second transmit beam being formed using the same aperture of the antenna array, wherein a skew angle of the first transmit beam is distinct from a skew angle of the second beam. Such radar system alternatively transmitting through subarrays and receiving each via the entire array and combining the signals such that the transmit and receive parts of one of two 2-way beams point in the same direction and the transmit and receive parts of the second 2-way beam point in the same direction and these directions are within a standard beamwidth of each other.
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2. The radar system of claim 1, wherein the aperture is the entire aperture of the antenna array.
3. The radar system of claim 1, wherein the separation between the first transmit beam and the second transmit beam is less than or equal to a beamwidth.
A radar system is designed to improve target detection and tracking by using multiple transmit beams with controlled separation. The system includes a radar transmitter configured to generate at least two transmit beams, where the separation between the first and second transmit beams is less than or equal to the beamwidth of the beams. This configuration ensures that the beams are closely spaced, allowing for precise targeting and enhanced resolution. The radar system also includes a receiver to process reflected signals from the transmit beams, enabling accurate determination of target position, velocity, and other characteristics. By maintaining a separation between the beams that does not exceed the beamwidth, the system minimizes gaps in coverage and improves detection reliability. This approach is particularly useful in applications requiring high-resolution tracking, such as military surveillance, autonomous navigation, and weather monitoring. The system may also incorporate additional features, such as beamforming techniques and adaptive signal processing, to further enhance performance. The close spacing of the transmit beams ensures continuous and overlapping coverage, reducing the likelihood of missed detections and improving overall system accuracy.
4. The radar system of claim 1, wherein the first transmit beam and the second transmit beam are made distinguishable on receive through at least one of time-division multiple access, code-division multiple access, or doppler-division multiple access.
5. The radar system of claim 4, wherein the first transmit beam and the second transmit beam are formed with opposing chirp waveforms.
6. The radar system of claim 4, wherein the first transmit beam and the second transmit beam are encoded as orthogonal phase shift keyed sequences.
7. The radar system of claim 1, wherein the first receive beam and the second receive beam are extracted according to at least one of time-division multiple access, code-division multiple access, or Doppler-division multiple access.
8. The radar system of claim 1, wherein the elevation angle of the target is determined according to at least one of amplitude-comparison monopulse, phase-comparison monopulse, or full-vector comparison monopulse.
9. The radar system of claim 1, wherein the elevation angle of the target is according to maximum likelihood estimation.
10. The radar system of claim 1, wherein the transmit portion is further configured to transmit a third transmit beam and a fourth transmit beam such that the first transmit beam, the second transmit beam, the third transmit beam, and the fourth transmit beam are distinguishable on receive, wherein the third transmit beam and the fourth transmit beam are formed from the single pulse and using the aperture of the antenna array, wherein the third transmit beam is transmitted with a third skew angle and the fourth transmit beam is transmitted with a fourth skew angle, the third skew angle and fourth skew angle being mutually distinct and being orthogonal to the first skew angle and the second skew angle, such that an azimuth angle of the target is determinable on receive.
12. The method of claim 11, wherein the first transmit beam and second transmit beam are formed using the entire aperture of the antenna array.
Antenna array systems for wireless communication often face challenges in achieving high-resolution beamforming while maintaining efficient use of the array's aperture. Traditional approaches may split the aperture into subarrays, which can reduce resolution or introduce complexity. This invention addresses these issues by forming multiple transmit beams using the entire aperture of the antenna array, enabling high-resolution beamforming without sacrificing aperture efficiency. The method involves generating a first transmit beam and a second transmit beam, both formed by the full aperture of the antenna array. This allows for precise beam steering and improved spatial resolution compared to subarray-based approaches. The beams may be used for tasks such as directional signal transmission, interference mitigation, or multi-user communication. The entire aperture is utilized for each beam, ensuring optimal performance without partitioning the array. The technique may be applied in phased array systems, massive MIMO, or other advanced wireless communication systems where high-resolution beamforming is critical. By leveraging the full aperture, the method enhances signal quality, reduces interference, and improves overall system efficiency.
13. The method of claim 11, wherein the separation between the first transmit beam and the second transmit beam is less than or equal to a beamwidth.
14. The method of claim 11, wherein the first transmit beam and the second transmit beam are made distinguishable on receive through at least one of time-division multiple access, code-division multiple access, or Doppler-division multiple access.
15. The method of claim 14, wherein the first transmit beam and the second transmit beam are formed with opposing chirp waveforms.
This invention relates to wireless communication systems, specifically methods for transmitting and receiving signals using multiple beams with opposing chirp waveforms. The problem addressed is improving signal detection and interference mitigation in environments where multiple transmit beams are used, such as in radar or wireless communication systems. The method involves transmitting a first signal using a first transmit beam and a second signal using a second transmit beam, where the beams are formed with opposing chirp waveforms. A chirp waveform is a signal whose frequency increases or decreases over time. By using opposing chirps (one increasing, one decreasing), the system can distinguish between the two beams more effectively, reducing interference and improving signal separation. The method also includes receiving reflected or transmitted signals from the beams and processing them to extract information, such as distance, velocity, or communication data. The opposing chirp waveforms allow for better discrimination between the two beams, particularly in scenarios where the beams overlap or interact. This technique can be applied in radar systems for object detection, wireless communication systems for data transmission, or other applications requiring precise signal differentiation. The method may also include adjusting the beam directions or waveforms dynamically to optimize performance based on environmental conditions or system requirements. The use of opposing chirps enhances signal clarity and reduces the likelihood of false detections or data corruption.
16. The method of claim 15, wherein the first transmit beam and the second transmit beam are encoded as orthogonal phase shift keyed sequences.
17. The method of claim 11, wherein the first receive beam and the second receive beam are extracted according to at least one of time-division multiple access, code-division multiple access, or Doppler-division multiple access.
This invention relates to wireless communication systems, specifically methods for extracting multiple receive beams from a signal to improve data transmission efficiency. The problem addressed is the need to efficiently separate and process multiple data streams in a wireless environment where signals may overlap or interfere with each other. The method involves extracting a first receive beam and a second receive beam from a received signal. These beams are separated using at least one of three multiple access techniques: time-division multiple access (TDMA), code-division multiple access (CDMA), or Doppler-division multiple access (DDMA). TDMA divides signals into different time slots, CDMA uses unique spreading codes to distinguish signals, and DDMA leverages differences in Doppler shifts caused by relative motion between the transmitter and receiver. The extracted beams are then processed to recover the transmitted data. This approach allows multiple users or data streams to share the same frequency band without significant interference, improving spectral efficiency and system capacity. The method is particularly useful in scenarios where multiple signals must be distinguished based on time, code, or frequency shifts due to motion. By employing these access techniques, the system can reliably separate and decode overlapping signals, enhancing communication performance in dynamic environments.
18. The method of claim 11, wherein the elevation angle of the target is determined according to at least one of amplitude-comparison monopulse, phase-comparison monopulse, or full-vector comparison monopulse.
19. The method of claim 11, wherein the elevation angle of the target is according to maximum likelihood estimation.
22. The radar system of claim 1, wherein the aperture is the entire aperture of the antenna array.
23. The radar system of claim 21, wherein the first receive beam and the second receive beam are separated from the third receive beam and the fourth receive beam by less than or equal to a standard beamwidth.
24. The radar system of claim 21, wherein the first transmit beam and the second transmit beam are made distinguishable on receive through at least one of time-division multiple access, code-division multiple access, or doppler-division multiple access.
25. The radar system of claim 24, wherein the first transmit beam and the second transmit beam are formed with opposing chirp waveforms.
26. The radar system of claim 24, wherein the first transmit beam and the second transmit beam are encoded as orthogonal phase shift keyed sequences.
27. The radar system of claim 21, wherein the first receive beam, second receive beam, third receive beam, and the fourth receive beam are extracted according to at least one of time-division multiple access, code-division multiple access, or Doppler-division multiple access.
28. The radar system of claim 21, wherein the elevation angle of the target is determined according to at least one of amplitude-comparison monopulse, phase-comparison monopulse, or full-vector comparison monopulse.
29. The radar system of claim 21, wherein the elevation angle of the target is according to maximum likelihood estimation.
A radar system is designed to accurately determine the elevation angle of a target. The system addresses the challenge of precisely estimating elevation angles in radar applications, which is critical for applications such as tracking, navigation, and surveillance. Traditional methods may suffer from inaccuracies due to noise, multipath interference, or limited resolution. This radar system improves upon prior approaches by employing a maximum likelihood estimation (MLE) technique to calculate the elevation angle of the target. MLE is a statistical method that identifies the parameter values that maximize the likelihood function, thereby providing a more robust and accurate estimation compared to simpler techniques. The system includes a radar transmitter and receiver configured to emit and detect radar signals, as well as processing circuitry that applies MLE to the received signals to derive the elevation angle. The use of MLE enhances the system's ability to handle noisy or ambiguous data, resulting in improved tracking performance. The radar system may also incorporate additional features such as beamforming, signal processing algorithms, and adaptive filtering to further refine the elevation angle estimation. By leveraging MLE, the system achieves higher precision and reliability in determining the target's elevation, making it suitable for demanding applications where accurate angle measurement is essential.
30. The radar system of claim 21, wherein the transmit portion is further configured to transmit a third transmit beam from a third subarray and a fourth transmit beam from a fourth subarray, such that the first transmit beam, the second transmit beam, the third transmit beam, and the fourth transmit beam are distinguishable on receive, wherein the third transmit beam is transmitted with a third skew angle and the fourth transmit beam is transmitted with a fourth skew angle, the third skew angle and fourth skew angle being mutually distinct and being orthogonal to the first skew angle and the second skew angle, such that an azimuth angle of the target is determinable on receive.
32. The method of claim 21, wherein the aperture is the entire aperture of the antenna array.
Antenna arrays are used in wireless communication systems to transmit and receive signals with high precision. A common challenge is optimizing signal transmission and reception while minimizing interference and signal loss. One approach involves controlling the aperture of the antenna array to improve performance. This invention describes a method for adjusting the aperture of an antenna array to enhance signal quality. The aperture refers to the active area of the array that participates in signal transmission or reception. By dynamically configuring the entire aperture of the array, the method ensures that the full potential of the antenna is utilized. This adjustment can be based on factors such as signal strength, environmental conditions, or user requirements. The method may involve selecting specific elements within the array to form the aperture, ensuring optimal signal coverage and reducing interference. The entire aperture of the array is adjusted to maximize efficiency, whether for transmitting or receiving signals. This approach improves signal clarity, reduces power consumption, and enhances overall system performance. The invention is particularly useful in applications requiring high-precision signal handling, such as 5G networks, satellite communications, and radar systems. By dynamically controlling the entire aperture, the method provides a flexible and efficient solution for modern wireless communication challenges.
33. The method of claim 21, wherein the first receive beam and the second receive beam are separated from the third receive beam and the fourth receive beam by less than or equal to a standard beamwidth.
34. The method of claim 21, wherein the first transmit beam and the second transmit beam are made distinguishable on receive through at least one of time-division multiple access, code-division multiple access, or doppler-division multiple access.
35. The method claim 24, wherein the first transmit beam and the second transmit beam are formed with opposing chirp waveforms.
36. The method of claim 24, wherein the first transmit beam and the second transmit beam are encoded as orthogonal phase shift keyed sequences.
37. The method of claim 21, wherein the first receive beam, second receive beam, third receive beam, and the fourth receive beam are extracted according to at least one of time-division multiple access, code-division multiple access, or Doppler-division multiple access.
This invention relates to wireless communication systems, specifically methods for extracting multiple receive beams from a signal to improve data transmission efficiency and reliability. The problem addressed is the need to efficiently manage and extract multiple receive beams in a wireless communication environment where signals may be subject to interference, multipath effects, or other challenges that degrade performance. The method involves extracting a first, second, third, and fourth receive beam from a received signal. These beams are processed using at least one of three multiple access techniques: time-division multiple access (TDMA), code-division multiple access (CDMA), or Doppler-division multiple access (DDMA). TDMA assigns different time slots to each beam, ensuring they do not interfere with one another. CDMA uses unique spreading codes to distinguish between beams, allowing multiple beams to share the same frequency and time resources. DDMA leverages Doppler shifts caused by relative motion between the transmitter and receiver to separate beams based on frequency shifts. By employing these techniques, the method enables efficient beam extraction, reducing interference and improving signal quality. The approach is particularly useful in scenarios where multiple beams must be managed simultaneously, such as in advanced wireless networks or satellite communications. The use of TDMA, CDMA, or DDMA ensures that the beams are processed in a way that maximizes spectral efficiency and minimizes collisions.
38. The method of claim 21, wherein the elevation angle of the target is determined according to at least one of amplitude-comparison monopulse, phase-comparison monopulse, or full-vector comparison monopulse.
39. The method of claim 21, wherein the elevation angle of the target is according to maximum likelihood estimation.
This invention relates to target tracking systems, specifically improving the accuracy of elevation angle estimation for moving targets. The problem addressed is the difficulty in precisely determining a target's elevation angle, which is critical for applications like missile guidance, radar tracking, and surveillance. Traditional methods often suffer from noise and measurement errors, leading to inaccurate tracking. The invention describes a method for estimating the elevation angle of a target using maximum likelihood estimation (MLE). MLE is a statistical technique that identifies the parameter values that maximize the likelihood of observing the given data. In this context, it processes sensor measurements—such as radar or lidar returns—to compute the most probable elevation angle of the target. The method accounts for measurement uncertainties and environmental factors, improving accuracy compared to simpler estimation techniques. The system may involve multiple sensors or a single sensor with multiple measurements over time. The MLE approach refines the elevation angle by iteratively adjusting the estimate to minimize the difference between observed and predicted measurements. This refinement reduces errors caused by noise, multipath interference, or sensor limitations. The method can be integrated into existing tracking algorithms to enhance performance without requiring significant hardware modifications. The invention is particularly useful in dynamic environments where targets move rapidly or where sensor data is noisy. By leveraging MLE, the system achieves more reliable elevation angle estimates, improving tracking precision and system reliability.
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January 4, 2021
November 22, 2022
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